In work vehicles such as hydraulic excavators, bulldozers, and the like, a hydraulic pump is driven by an engine, and a hydraulic actuator is driven by hydraulic fluid discharged from the hydraulic pump. In such work vehicles, the engine and the hydraulic pump are controlled in such a way that the output torque of the engine and the absorption torque of the hydraulic pump are matched at a target matching rotation speed of the engine, as shown in Japanese Laid-open Patent Application 2007-120425. In specific terms, a target absorption torque of the hydraulic pump is calculated in such way that the output torque of the engine and the absorption torque of the hydraulic pump are matched to the target matching rotation speed.
Meanwhile, the absorption torque of the hydraulic pump is controlled through electrical control of a pump control device that controls the hydraulic pump. Specifically, the absorption torque of the hydraulic pump is controlled in accordance with a command value of a command signal to the pump control device. Once the target absorption torque is calculated in the above manner, a command value corresponding to the target absorption torque is calculated, and a command signal corresponding to this command value is input to the pump control device. Herein, the command value of the command signal is calculated making reference to command data. The command data is information showing correspondence between the command value of the command signal to the pump control device, and the absorption torque of the hydraulic pump. Command data is composed of data prepared beforehand through experimentation in the work vehicle design stage, and is stored in a storage unit.